Personnel lifts are presently used for a wide variety of applications. Personnel lifts generally include an aerial work platform that can be raised or lowered to position a worker at a desired height. Personnel lifts can be used within a plant to raise a worker to a position where the worker can change light bulbs, work on fixtures, or paint overhead surfaces, for example.
In one personnel lift design, the aerial work platform is attached to the upper end of a vertical lift assembly and includes a personnel cage for containing a worker. The vertical lift assembly includes a tower of extendible, nested columns mounted on a base supported by wheels. The tower and base are small so that a worker can easily roll the base to a desired location. Once the personnel lift is placed in the desired location, a number of outriggers are set to stabilize the base. Alternatively, the personnel lift may utilize corner jacks and legs such as are disclosed in U.S. Pat. No. 5,337,858 (the '858 patent). After the personnel lift has been adequately stabilized, a worker enters the personnel cage and operates controls to raise the aerial work platform.
A worker performing tasks in several overhead locations may find it necessary to move a personnel lift a number of times during the day. In general, once the aerial work platform is lifted to the desired height, the worker is limited to doing work in an area that is within arm's length of the aerial work platform. If the worker desires to do work beyond that reach, he or she must lower the aerial work platform, exit the personnel cage, release the outriggers from their secured position, and move the personnel lift to the next desired location. The outriggers must once again be set before the worker can return to the personnel cage and raise the aerial work platform to the desired height.
The personnel lift set forth in the '858 Patent is particularly advantageous in that a worker may rely on corner jacks and legs to stabilize the base of the personnel lift without having to manipulate retractable or removable outriggers. The foot pads and corner jacks are retracted so that the base is supported on caster wheels and may be pushed to a desirable location. However, the device set forth in that patent is not easy to manipulate around a room because no mechanism for steering the caster wheels or easily leading the base to a desired location is included.
There is a need in the art for a more efficient personnel lift that is easily moved to a variety of locations and quickly and easily stabilized.